Background In many cases standard management for chronic fatigue syndrome (CFS) in children and adolescents is ineffective.

Objective To evaluate the efficacy of a video film intervention in preventing the development of persistent fatigue and significant school absence in fatigued children and adolescents.

Design Randomised controlled trial.

Participants 91 patients with fatigue; 50 were randomly assigned to receive the intervention (video film plus usual care) and 41 to usual care only.

Intervention A video film on CFS and coping behaviour.

Main outcome measures Self-reported fatigue severity, physical activity, motivation, concentration and school absence.

Results 79 patients had complete data at 12 months (42 in the video film and 37 in the usual care group). Mean fatigue severity and school absenteeism scores did not differ significantly, but in the intervention group the score for reduced motivation was higher (difference 2.9 (CI 0.1 to 5.7), p=0.038). 18% more patients in the intervention compared to the usual care group also had persistent fatigue with significant school absence. The odds of developing persistent fatigue and of missing >50% of school classes was 3.3 times higher in the intervention than in the usual care group (OR 3.3 (CI 1.0 to 11.3), p=0.046).

Conclusion This particular video film intervention plus usual care in children and adolescents with unexplained fatigue did not prevent an unfavourable outcome and possibly had an adverse effect in that it reduced motivation and increased the incidence of persistent fatigue with significant school absence. The use of this particular film is not recommended.